High performance visible light photodetector based on TlInSSe single crystal for optoelectronic devices

Owing to its high photosensitivity and excellent optoelectrical properties in the visible range, the TlInSSe single crystal is considered for use in high performance visible photodetectors. Herein, we report a detailed optoelectrical investigation of TlInSSe single crystal grown via the Bridgman technique. The photocurrent was observed to increase with an increase in the illumination intensity. The temperature-dependent photoconductivity under different illumination intensities was studied to understand the photogenerated charge transport mechanism in the TlInSSe crystal. A drop in activation energy was noticed from 0.278 eV (under dark conditions) to 0.114 eV (under illumination), attributed to the filling of trap states by photogenerated carriers. The photo-switching behavior was studied and the growth and decay times were found to be ∼310 and 300 ms, respectively. The photodetector device of the grown crystal was fabricated and the important figure of merit was determined for 532 nm laser light. The photodetector exhibits a responsitivity up to 0.61 A W−1, a detectivity up to 6.24 × 1011 Jones, and an external quantum efficiency up to 120%. These parameters decrease with an increase in the illumination intensity, but increase with applied voltage. These excellent optoelectrical properties make TlInSSe single crystal a highly competitive candidate for visible photodetector devices.